Married with a 2 year old and another one on the way. You can definitely keep having fun with your hobbies. If she is really the one for you, she will actually support you in doing what you enjoy, but within reason.
My wife loves that I love my car. She actually encouraged me to get it when I thought something different might be more reasonable for a growing family. She has a Lexus with 3rd row seating so we really dont need another large SUV, so it worked out for me.
When kids enter the mix, your priorities definitely change, but you can still do stuff you like to do. With my previous e90, I had fun putting on some mods. At this point, I would rather spend time with my 2 year old that wants to play swords and fight monsters than go out and fiddle with my car. I want to enjoy my time with him now and when the baby is born, but I still do littel projects now and then. But of course, he gets new clothes, shoes, school supplies, whatever else he needs before I think about anything else for my car. When my little girl comes in June, it will be bows and dressies, and anything else she needs.
Its really about how supportive your wife is, what your situation is, how much you can allocate to spending on your car, and what your priorities are. I will always have a car that I can mod, but my kids are going to grow up fast. I dont want to miss any of it at this point. When my son is older, I will actually get him out in the garage, and we can work on stuff together.
So you dont have to sacrifice everything you like to do just because you get married or start having kids. Good luck bro!